Means for regulating internal combustion engines



1935 N J. WHARTON 2,022,511

MEANS FOR REGULATING INTERNAL COMBUSTION ENGINES Filed Nov. 14, 19 33 2Sheets-Sheet 1 Fig.1; v

Fig. 5. g D

26, 1935. N J, WHARTQN 2,022,611

MEANS FOR REGULATING INTERNAL COMBUSTION ENGINES Filed Nov. 14, 1955 2Sheets-Sheet 2 iii //V VE N 701? f Vii/#2701 Patented Nov. 26, 1935UNITED STATES PATENT OFFICE MEANS FOR REGULATING INTERNAL COMBUSTIONENGINES Application November 14, 1933, Serial No. 698,001 In GreatBritain December 2, 1932 2 Claims.

The present invention relates to internal combustion engines which areintended to operate over a considerable range of speeds and isparticularly but not exclusively applicable to engines 5 of the liquidfuel injection compression ignition type.

The object of the invention is to reduce or prevent the risk of anengine operating under conditions of torque in relation to its speedwhich are undesirable.

To this end according to the present invention an internal combustionengine having a control member whereby the quantity of fuel orcombustible charge delivered during each cycle can be varied is providedwith a governor responsive to variations in the speed of the engine andmeans controlled by the governor whereby the maximum quantity of fuel orcombustible charge which can be delivered is limited to an amount whichis diiferent at different engine speeds.

As stated, the invention is particularly applicable to engines of theliquid fuel injection compression ignition type and when applied to suchengines the speed-responsive governor acts through suitable mechanism tolimit the movement of the member for varying the quantity of fueldelivered on each delivery stroke of the fuel pump in such a manner thatthe maximum quantity of fuel which can be delivered at each deliverystroke is limited but is different at different engine speeds.

In certain circumstances it is desirable that an engine which has towork over a considerable range of speeds should not be capable of givingsuch a high maximum torque at certain speeds as at others the torquegiven being capable of being varied however at all speeds to suitdifferent load conditions and it will be seen that with the presentinvention it is possible to ensure that the maximum torque at any speedcannot exceed that desirable for such speed without however limitingunnecessarily the maximum torque at speeds where a high maximum torqueis desirable.

In a convenient arrangement according to the invention an adjustablestop member, conveniently in the form of a cam, serving to limit themovement of the fuel pump control member in a direction to increase thequantity of fuel injected 50 is actuated directly or indirectly by thegovernor so as to limit the movement of the control member to an extentwhich depends on and varies with the engine speed whereby the maximumload carried by or the maximum torque exerted by the 55 engine can belimited to a valuewhich for each speed is the maximum which is desirableat that speed.

For example in one known form of fuel injection pump the quantity ofliquid fuel delivered by the pump on each delivery stroke is controlled5 by a longitudinally movable member and when the invention is appliedto such a fuel pump the mechanism for limiting the movement of thismember may comprise a face cam which is rotatable by the governor andforms an adjustable 10 stop against which the control member or a partformed or rigidly mounted thereon comes into contact when this controlmember is moved in a direction to increase the quantity of fueldelivered. 15

Preferably the arrangement is such that the maximum quantity of fuelwhich can be delivered at very low speeds corresponding to startingconditions is substantially greater than that which can be delivered athigher speeds corresponding 20 to running conditions since for startingpurposes large quantities of fuel may be required. For example, where acam constituting a stop is employed, as described above, a-very steepsurface or slot on the cam face may be provided to permit 25 movement ofthe fuel pump control member considerably beyond its normal maximum loadposition when the cam occupies the starting position. Thus the injectioninto the cylinder of the excess fuel which is desired during starting isper- 30 mitted whereas as soon as the engine is running the maximumquantity of fuel which can be delivered is reduced to the normal.

The maximum quantity of fuel which can be injected may. be arranged tovary with the speed 35 in accordance with any desired curve or lawaccording to the characteristics of the engine to which the invention isapplied and the purpose for which it is intended.

The invention is particularly but not exclusive- 40 ly applicable toengines of the kind in question for motor road vehicles and one form ofthe invention applicable to an engine having a fuel pump in which theamount of fuel delivered on each delivery stroke is controlled either byrotat- 45 ing the pump plunger which acts also as a spill valve or byrotating a separate spill valve by means of a longitudinally movablerack is illustrated somewhat diagrammatically by way of example in theaccompanying drawings, in which Figure 1 is a side elevation, partly insection, of. the governor and the apparatus controlled therey,

Figure 2 is a plan view, also partly in section, of part of theconstruction shown in Figure l,

Figure 3 is an inverted plan view of the mechanism shown in Figure 2,

Figure 4 is a development of the cam shown in Figures 2 and 3, and VFigure 5 is a view, on a reduced scale, of an engine to which theapparatus shown in Figures 1, 2, 3 and 4 is applied. 7

In the construction illustrated the apparatus comprises a centrifugalgovernor driven by the engine and having weights in the form of balls Aresting in radial grooves or tracks on the inner surface of a rotatingcup C mounted on a shaft A which is driven by suitable gearing from thecrankshaft A of V the engine A for example through a gear wheel C. Theballs A are held in their tracks by the pressure of theface of a disc Dwhich is mounted so that it can slide axially on a sleeve D surroundingthe shaft A and is urged towards the balls A by one end of a spring Dthe other end of which bears on a thrust member D connected to the shaftA by a thrust bearing D The disc D is connected to one arm E of a leverpivoted at E sothat axial movement of the disc D causes the lever E torock about the pivot E The other :arm E of the pivoted lever is formedas a cam on which bears a follower F in the form of a'roller connectedto a rack member F pivoted at F and acted upon by a spring F tending tomaintainthe follower F always in contact with the face of the cam E Theteeth of the rack F mesh with a gear wheel G formed or rigidly mountedon a sleeve G rotatably supported in a bearing G Passing freely throughthe bore of the sleeve G is the end portion of a longitudinally movablerod H constituting the member controlling the quantity of fuel deliveredby a fuel pump J, this control being effected, for example, in knownmanner by a rack H formed on the member H engaging a gear wheel H on theend of a member H which constitutes or is connected to the spill valveof the fuel pump, this pump being constructed in known manner so thatrotation of the spill valve varies the quantity of fuel delivered. 7

Formed on one end of the sleeve G is a cam surface G which is adapted tocooperate with a pin H on the rod H so as to limit the movement of thisrod in a direction to increase the quantity of fuel delivered by thefuel pump; The face cam G has the general form shown in development inFigure 4 and is provided with a groove which at one'rotary position ofthe sleeve G receives the pin H and thereby permits movement of the rodH to increase the quantity of fuel delivered by the pump beyond thenormal maximum.

It will be seen that with the arrangement described above movement ofthe disc D as a result of variations in the speed of the engine actsthrough the lever E, E to produce movement of the rack F and hence tocause rotary movement of the sleeve G 'Thus at different speedsdifferent parts of the cam face G lie opposite the pin H so that themovement of the rod H to increase the quantity of fuel injected is1imited to an extent which varies with variations in the speed of theengine.

The form of the cam face may vary but in the arrangement shown moreparticularly in Figure 4 the groove indicated by the reference letter Gis adapted to'lie opposite the pin when the engine is at rest or isrotating at very slow speeds corresponding to starting speeds so thatfor this position of the sleeve G the member H can be moved to increasethe quantity of fuel delivered by the pump considerably above themaximum normal quantity as is sometimes required for starting purposes.During normal running of the engine, however, the part of the cam faceindicated by the letter G comes opposite to the pin so that the movementof the rod H to increase 5 the quantity of fuel delivered is limited toan extent which is determined by the speed of the engine. Thus, as thespeed increases from low speeds to mean speeds, the maximum movement ofthe rod to increase the quantity of fuel in- 10 creases, while as thespeed increases still further from mean speeds towards the maximumspeed, the maximum movement of the rod H to increase the quantity offuel is again reduced. As an example in Figure 4 the maximum movement of15 the rod H at the mean speed of the engine from its maximum injectionto its minimum injection position is indicated by the two positions forthe pin H indicated in Figure 4 respectively by the reference letters Hand H while the position 20 which the pin may occupy at the very slowstarting speed is indicated by the reference letter 1-1 It is to beunderstood that the form of the cam shown is only given by way ofexample and that the form mayvary widely according to. re- 5.

quirements. For example in one modified, arrangement the cam may be soformed that the maximum quantity'of fuel which can be delivered isgreatest when the engine speed is ata maximum and is gradually reducedas the engine speed 30 1 speed as described in the presentapplicants co-40 pending United States patent application No. 698,000, filed November14, 1933.

What I claim as my invention and desire to secure by Letters Patent is:-

1. An internal combustion engine of the vari- 5 able speed liquid fuelinjection compression ignition type including in combination a fuelpump, a control member whereby the quantity of fuel delivered on eachdelivery stroke can be varied, a governor driven by the engine andresponsive to variations in the speed of the engine, and an adjustablestop actuated by the governor and serving to limit the movement of thecontrol member in a direction to increase the quantity of fueldelivered, this stop member having a cam surface thereon whereby thepoint in the movement of the control member at which the stop memberprevents further movement thereof is de-' termined by and varies withvariations in the engine speed, the cam surface being so formed that atlow speeds corresponding to starting conditions the control member canbe moved into a position in which a quantity of fuel is deliveredsubstantially greater than the maximum which is permitted at the higherspeeds corresponding to running conditions;

2. For use with an internal combustion engine of the variable speedliquid fuel injection compression ignition type, a fuel pump includingin combination a control member for varying the quantity of fueldelivered, an adjustable stop member adapted to be actuated by agovernor and serving to limit the movement of the control member in adirection to increase the quantity of fuel delivered, this stop memberhaving a cam surface thereon whereby the point in the movement of thecontrol member at which the stop member prevents further movementthereof is determined by and varies with movement of the stop, theformation of the cam surface being such that at the position the stop isintended to occupy at low speeds corresponding to starting conditionsthe control member can be moved into a position in which a quantity offuel is delivered substantially greater than the maximum which ispermitted at higher speeds corresponding to running conditions.

JOHN WHARTON.

